Two new inorganic-organic hybrid compounds templated by SiW_(12)O_(40)~(4-) anion with nonlinear ligands

摘要

Two new Keggin-type polyoxoanion-templated inorganic-organic hybrids, [Cu(3,4-bpo)_2(H_2O) (SiW_(12)O_(40))l ? (3,4-H_2bpo) ? 7H_2O (1), and [Cu(4.4'-Hbpo)_2(4,4'-bpoXH_2OXSiW_(12)O_(40))] ? 3H_2O (2) (3,4-bpo = 2-(3-pyridyI)-5-(4-pyridyl)- 1,3,4-oxadiazoIe, 4,4'-bpo = 2,5-bis(4-pyridyl)-l,3,4-oxadiazole), have been hydrothermally synthesized by changing the terminal N-donor's orientation of the nonlinear ligands. X-ray structural analyses indicate that compound 1 shows a two-dimensional (2D) (4,4) grid sheet. The discrete SiW_(12)O_(40) anions as templates locate on the square voids of the sheet. Compound 2 exhibits an arm-shaped chain structure. It is believed that the isomeric organic ligands play a key role in the structure control of the self-assembly processes. Furthermore, compound 1 bulk-modified carbon paste electrode (1-CPE) displays good electrocatalytic activity toward the reduction of nitrite.